Inertia responsive device



Aug. 19, 1947.

M. G. LEONARD 2,426,034

INERTIA RESPONS IVE DEVICE Filed June 18, 1945 WITNESS INVENTOR w. Merrfl/ 5 [award BY :Puv/

ATTORNEY Patented Aug. 19, 1947 UNITED STATES PATENT OFFICE INERTIA RESPONSIVE DEVICE Application June 18, 1943, Serial No. 491,322

8 Claims. 1

My invention relates to electric switches and more particularly to inertia responsive switches for closing a circuit when the switch is subjected to a mechanical shock.

The Government of the United States has been granted a certain royalty-free license for governmental purposes with respect to the invention herein described.

Inertia responsive switches are well known in the art but usually such switches are complicated, expensive, and not particularly reliable.

In torpedoes some device usually has to be provided for detonating the charge when the torpedo is subjected to a shock. It is readily apparent, without elaborate proof, that for such application an inertia responsive torpedo detonating device must operate every time and only when called upon to operate. An element of chance must not be allowed to enter in the operation. It is a known fact of machine design that the simpler the machine the more reliable.

One broad object of my invention is the provision of an inertia responsive device of the simplest and most reliable character for its intended purpose.

Another and somewhat more specific object of my invention is the provision of an inexpensive and reliable inertia responsive switch that will perform its intended operation regardless of the direction of the force causing operation of the inertia responsive part of the switch.

A further object of my invention is the provision of reliable detonation of a torpedo when subjected to a shock.

The objects specifically hereinbefore recited are merely illustrative of many other objects of my invention. The other objects thereof will become more apparent from the following more detailed disclosure including specifications and claims, and the accompanying drawing, in which:

Figure 1 is a horizontal sectional view on the plane normal to Fig. 3 indicated by line I-I on Fig. 3 and looking in the direction of the arrows at the ends of line II;

Fig. 2 is a vertical sectional View on the plane normal to Fig. 3 indicated by line II--II of Fig. 3 and looking in the direction of the arrows at the ends of the line II--II;

Fig. 3 is a vertical sectional view on the plane normal to Fig. 1 indicated b line IIIIII of Fig. 1 and looking in the direction of the arrows at the ends of the line IIIIII;

Fig. 4 is a vertical sectional view on the plane normal to Fig. 3 indicated by line IV-IV on Fig.

3 and looking in the direction indicated by the arrows at the ends of line IV-IV; and

Fig. 5 is a diagrammatic showing of my invention in its principal combination.

To provide the simplest and most reliable construction of my invention I bend a single strip of metal into an open-ended rectangular box I as can be readily seen from Figs. 2 and 4. At the corners, as points 2 and 3 and other points along the box or base, I spot-weld the contiguous edges to form a rigid base. By means of a pair of tie rods, as 4 and 5, I seal up the base or box ends with end plates 6 and l. The structure inside the base, which is, of course, mounted before the end plates are placed in position, is thus sealed within a base free from dust or dirt that might possibly interfere with the proper operation of my inertia switch.

Transverse of the base I position the pivot pin ii forming a common pivot for the two flat levers 9 and It. These levers are disposed in spaced substantially parallel relation to each other, being pivoted on the pin 8 by suitable ears projecting from these levers, as shown. These levers thus mounted operate on the mechanical principle of a tong.

The left-hand ends of the levers or jaws, of the tong, are provided with circular openings H and I2 extruded outwardly as shown. These openings are in axial alignment and thus form a cage, or holder, for the inertia member l3. This inertia member is preferably a brass ball, or sphere, provided with the polar projections l4 and I5 and the equatorial enlargement I6. These projections and the enlargement keep the inertia member in proper position in relation to the lefthand jaws of the tong.

To prevent the weight of inertia member l3 from resting on the levers, particularly the lower lever H! a spring I! is disposed as shown about the raised portion l8 and projection l5 on the inertia member. This spring I1 is selected to have a biasing force just suflicient to hold the inertia member [3 and such unbalanced portion of the left ends of the levers 9 and ID in the position shown.

My device is shown to full scale and, normally is mounted in the torpedo in the position shown in Fig. 3 where projections l4 and I5 are on a substantially vertical axis. The gyroscopic control and other control of the torpedo, but which are not part of this invention, are charged with the duty of maintaining this axis of the projections I4 and I5 vertical.

At the right-hand jaws of the tong, considering the two levers and mounting as a tong, I mount a pair of electrical contact members 19 and 20 on suitable blocks of insulation as shown. The contact members are spaced and insulated from the levers and have the terminals 2i and 22 which are electrically connected to the outer terminals 23 and 24 by flexible leads 25 and 26. These leads 25 and 25 are of soft and flexible material and thus do not in the least interfere with the proper operation of the other parts of my device.

About the spacing blocks of insulation at the right-hand end of levers 9 and I I place a soft spring 36 to normally hold the contact member l9 and apart. This spring 30 also causes the left-hand ends of levers 8 and iii to move con tiguous to the spherical inertia member It.

My device is so mounted in the torpedo that end plate I faces the inner front wall of the torpedo war head. The normal force of impact on the torpedo and thus on my device is from left to right in Figs. 1 and 3, or from right to left in Fig. 5. There is no assurance, however, that the impact on the torpedo will be in any such selected direction. Provision must, therefore, be made for reliable operation regardless of the direction of the force of impact. To this end I provide pins or bolts, 3! and These bolts are axially adjustable and once adjusted are held in proper adjustment by suitable lock-nuts as shown.

As seen in Fig. 2, the upper lever ii has its nearer left-hand corner cut away at 33 the lower lever It! has its nearer right-hand corner cut away at 3 4. For proper operation the bolt 3'! is adjusted and locked so that its lower end engages the nearer left-hand corner of lever Hi, the adjustment being such that lever is positioned substantially horizontally. The exact adjustment will depend somewhat on the lifting force of spring H on inertia member iii. In any event bolt 3| is so adjusted that the flaring err-- trudedl portion at opening l2 just makes contact with the spherical surface of the inertia member i3 but carries substantially no portion of the weight of inertia member 13.

The bolt 32 is then adjusted and locked so that its upper end engages the near right-hand corner of lever 9 to hold lever 9 substantially horizontal, but primarily in such position that the flaring extruded portion at opening ll makes light contact with the upper spherical portion of inertia member [3.

From the two preceding paragraphs it will be apparent that lever 9 can rotate clockwise only, looking at Fig. 3, and lever Hi can rotate counter clockwise only, still looking at Fig. 3. Any inn-- pact on the torpedo, and thus the switch base, regardless of the direction of the force will cause contacts I!) and 20 to close and thus cause detonation of the torpedo. Looking at Fig. 5, if the impact force is acting generally from the front toward the rear, and considering pin 8 as the part fixed to the torpedo, the inertia member moves forward and thus causes both levers 9 and Hi to rotate, lever 9 rotates counterclockwise and lever l0 rotates clockwise. The same action takes place if the impact force acts from the rear toward the front.

If the impact force is from above, inertia member l3 moves upwardly with reference to case i, but since lever Iii, by virtue of the stop action of bolt 3!, cannot partake of this motion, lever 9 moves countercloclnvise to move contact member I9 toward, at this time, stationary contact 23. If the impact is from below inertia, member i3 moves downwardly with reference to case I. Lever 9 cannot partake of this movement. Lever ii] is moved clockwise moving contact 20 toward, at this time, stationary contact member [9.

In Fig. 5, B represents the source of energy for operating the detonator D when switch contacts l9 and 20 and the contacts 35 and 36 of one safety switch 31 and contacts 38 and 39 of another safety switch 40 are closed. Safety switches 31 and 40 may be of the thermostatic type latched to open position until a thermostat for each one has been heated enough to release the latch to permit closure of the contacts 35 and 36, and 38 and 39, respectively. One preferred arrangement is to have contacts 35 and 36 close soon after firing of the torpedo and have contacts 38 and 39 close after a predetermined distance of travel of the torpedo. These safety switches 37 and 40 are no part of this invention but are disclosed in other patent applications of mine.

The disclosure and showing I have made of my novel inertia responsive switch are not to be taken in a limiting sense but are illustrative. My invention, therefore, is to be limited only by the scope of the claims hereto appended.

I claim as my invention:

1. In an inertia responsive device, in combination, a base subject to shock in normal use, a pair of parallelly disposed levers pivoted intermediate their ends on the base, outwardly extruded openings in axial alignment with each other in two of the adjacent ends of the levers, a generally spherically shaped inertia member disposed between the levers and opposite relatively small spherical segments of the inertia member fitting into the aligned openings of the levers, whereby any movement of the inertia member relative to the levers causes the ends between which the inertia member is positioned to move away from each other and the other free ends of the levers to move toward each other, and switch means disposed in operable relation to said free ends to be operated by the levers upon movement of the inertia member when the base is subjected to a mechanical shock.

2. In an inertia controlled device, in combination, a base which in normal use is subject to shock, a pair of parallelly disposed levers pivoted intermediate their ends on the base, outwardly extruded openings in axial alignment with each other in two of the adjacent ends of the levers, a generally spherically shaped inertia member dispOSed between the levers and opposite relatively small spherical segments of the inertia member fitting into the aligned openings of the levers, means for holding the inertia member in balanced position so that its weight is not carried by the levers, whereby any movement of the inertia member relative to the levers causes the ends between which the inertia member is positioned to move away from each other and the other or free ends of the levers to move toward each. other, and a normally open switch disposed at the free ends of the levers to be operated to a closed position by the operation of the levers by the inertia member upon subjecting the base to a mechanical shock.

3. In an inertia responsive device, in combination, a base, a pair of parallelly disposed levers pivoted intermediate their ends on the base, outwardly extruded openings in axial alignment with each other in two of the adjacent end of the levers, a generally spherically shaped inertia member disposed between the levers and opposite relatively small spherical segments of the inertia member fitting into the aligned openings of the levers, whereby any movement of the inertia member relative to the levers causes the ends between which the inertia member is positioned to move away from each other and the other or free ends of the levers to move toward each other, means for biasing the other or free ends of the levers away from each other to thus cause the inertia member to be gripped by the lever ends between which the inertia member is positioned, and a normally open switch disposed at the free ends of the levers to be operated to closed position by movement of the levers by the inertia member upon subjecting the base to a mechanical shock.

4. In an inertia responsive device, in combination, a base, a pair of parallelly disposed levers pivoted intermediate their ends on the base, outwardly extruded openings in axial alignment with each other in two of the adjacent ends of the levers, a generally spherically shaped inertia member disposed between the levers and opposite relatively small segments of the inertia member fitting into the aligned openings of the levers, means for holding the inertia member in balanced position so that its weight is not carried by the levers, whereby any movement of the inertia member relative to the lever causes the ends between which the inertia member is positioned to move away from each other and the other or free ends of the levers to move toward each other, means for biasing the other or free ends away from each other to cause the inertia member to be gripped by the lever ends between which the inertia member is positioned, and switching means disposed at the free ends of the levers to be operated by the levers upon movement of the levers by the inertia member when the base is subjected to a mechanical shock.

5. In an inertia responsive device, in combination, a base in normal use subject to shock, a pair of levers mounted for tong-like action having their common pivot point mounted in fixed relation with reference to the base, an inertia member disposed between one pair of jaws of the tong levers and having cam surfaces for separating the arms upon movement and in a direction of the inertia member with reference to the base, and switching means associated with the other jaws of the tongs adapted to be moved to an upward operative position upon movement of the other jaws of the tong levers.

6. In an inertia responsive device, in combination, a base in normal use subject to mechanical shock, a pair of levers mounted for tong-like action on the base, the common shaft of the levers being fixed in relation to the base, one pair of adjacent jaws of the tongs having aligned openings and the other pair carrying facing electrical contact members, an inertia member disposed between the jaws having the openings and having cam surfaces projecting into the openings, said jaws between which the inertia member is mounted being caused by the inertia member upon subjecting the base to a mechanical shock to move relatively away from each other to thus cause the electric contact members at the other jaws to contact each other.

7. In an inertia responsive device, in combination, a base in normal use subject to mechanical shock, a pair of levers mounted for tong-like action on the base, the common pivot of the levers being fixed in relation to the base, one pair of adjacent jaws of the tongs having aligned openings and the other pair carrying facing electric contact members, an inertia member disposed between the jaws having the openings and having cam surfaces projecting into the openings, resilient means for holding the inertia member in balanced position so that the weight of the inertia member is not carried by the jaws, said jaws, between which the inertia member is mounted, being caused by the inertia member upon subjecting the base to a mechanical shock to move relatively away from each other to thus cause the electric contact members at the other jaws to contact each other.

8. In an inertia responsive device, in combination, a base in normal use subject to mechanical shock, a pair of levers mounted for tong-like action on the base, the common pivot of the levers being fixed in relation to the base, one pair of adjacent jaws of the tongs having aligned openings and the other pair carrying facing electric contact members, an inertia member disposed between the jaws having the openings and having cam surfaces projecting into the openings, resilient means for holding the inertia member in balanced position so that the weight of the inertia member is not carried by the jaws, resilient means disposed between the other jaws to bias the other jaws away from each other to thus cause movement of the jaws in close proximity to grip the inertia member, means for limiting the movement of the jaws between which the inertia member is mounted toward the inertia member, said jaws, between which the inertia member is mounted, being caused by the inertia member upon subjecting the base to a mechanical shock to move relatively away from each other to thus cause the electric contact members at the other jaws to contact each other.

MERRILL G. LEONARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,202,043 Cale May 28, 1930 1,623,475 Hammond Apr. 5, 1927 FOREIGN PATENTS Number Country Date 137,860 Great Britain Jan. 5, 1918 318,029 Germany Jan. 9, 1920 703,595 Germany Mar. 12, 1941 246,995 Italy Apr. 15, 1926 

